Computational and Functional Analysis of Structural Features in the ZAKα Kinase

Abstract

The kinase ZAKα acts as the proximal sensor of translational impairment and ribotoxic stress, which results in the activation of the MAP kinases p38 and JNK. Despite recent insights into the functions and binding partners of individual protein domains in ZAKα, the mechanisms by which ZAKα binds ribosomes and becomes activated have remained elusive. Here, we highlight a short, thrice-repeated, and positively charged peptide motif as critical for the ribotoxic stress-sensing function of the Sensor (S) domain of ZAKα. We use this insight to demonstrate that the mutation of the SAM domain uncouples ZAKα activity from ribosome binding. Finally, we use 3D structural comparison to identify and functionally characterize an additional folded domain in ZAKα with structural homology to YEATS domains. These insights allow us to formulate a model for ribosome-templated ZAKα activation based on the re-organization of interactions between modular protein domains. In sum, our work both advances our understanding of the protein domains and 3D architecture of the ZAKα kinase and furthers our understanding of how the ribotoxic stress response is activated.

Nitric oxide-induced ribosome collision activates ribosomal surveillance mechanisms

“…This was in contrast to UV-B irradiation, where only nucleotide damage in the mRNA fraction negatively affected in vitro translation (Fig. 3d ), consistent with previous results [ 8 ]. Addback of untreated cytoplasmic fraction only partially restored cap-dependent luciferase production (Fig.…”

“…One MAP3K that has recently risen to prominence is the ZAKα kinase. Through its binding to the ribosome via two C-terminal domains, ZAKα functions as a sensor of translational impairment [ 7 , 8 ] and is activated upon stalling and/or collisions of ribosomes [ 9 , 10 ]. Sensing of such structures induces the autophosphorylation and activation of ZAKα through poorly understood mechanisms and subsequent signaling through the downstream MAPKs, p38, and JNK.…”